Wire spoke for wheels



Nov. 10,1925. 4 1,560,565

. J. H.'GRAHAM WIRE SPOKE FOR WHEELS Filed May 24, 1922 I /wan f 12y! 12g 2 J 'INVENTOR.

wines/1. drafiafiz ATTO i Patented Nov. 10, 1925.

UNITED STATES JAMES H. GRAHAM, OF TORRIN'GTON, CONNECTICUT.

WIRE SPOKE non WHEELS.

Application filed May 24, 1922. Serial No. 563,402.

To all whom it may concmm:

Be it known that I, JAM S H. GRAHAM, a citizen of the United States, and a resident of Torrington, county of Litchfield, and State of Connecticut, have invented certain new and useful Improvements in W'ire Spokes for Wheels, of which the following is a specification.

This invention relates to bicycle, automobile, and aeroplane wheels and more particularly to an improved form of wire spoke for use in such wheels. p

One object of the invention is to provide a wire spoke so constructed that the amplitude of the harmful vibrations transmitted to said spoke from the wheels will be reduced to the minimum. i

A further objectis to provide a wine spoke in which the vibration strains will be uniformly distributed.

A further object is to provide a spoke so constructed that its weakest point will be in the central portion thereof, so that in case of breakage, the rupture of the spoke will always take place at the center rather than at the ends thereof.

A further objectis to provide a spoke which will be simple, cheap to manufacture, and very efficient and durable in use. 7

Vith these and other objects in view, there has been illustrated on the accompanying drawings one form in which the invention may be conveniently embodied in practice.

Fig. 1 is a side elevation of a complete spoke embodying the principles of the invention.

Fig. 2 is a side elevation on an enlarged scale of the central portion of the spoke shown in Fig. 1.

In the ordinary wire spokes used for vehicle wheels, it has been customary in the past, to form the entire length of such spokes of uniform diameter except for short sections near each end, which were of larger diameter.

It has been found in practice in the use of such spokes that there was a tendency for them to break under the repeated stresses to which they were subjected in passing over the roadways. and that the breakage generally took place at the shoulders between the small and largediameter sections of the spoke. This breakage was due to an injurious vibration or rapid alternate bending of the wire, and since the greatest strain per unit area occurred at the junctions: of the large and small sections of the wire, the rupture naturally took place at these points.

By means of the present invention, the above and other disadvantages have been largely overcome. This has been accomplished by constructing the spoke with a relatively short central cylindrical section ofvsma-ll' diameter, and relatively long end sections of larger diameter, said central and end sections being joined by a pair of relatively long tapered sections. The provision of a short central section of reduced area in the spoke serves to break up the natural free vibrations of the spoke into two halves the central section acting as a node. Thus the centre of the spoke, instead of having the maximum amplitude of vibration. of any point between-the fixed ends of the spoke, will remain practically stationary. Any vibration which then occurs takes place in the two halves of the spoke and the angular bending strains at the rim and hub are consequently very greatly reduced. No portion of the spoke even under very severe operating conditions therefore can be subjected to injurious strains which might result in metal fatigue or crystallization.

Referring now to the drawings, the spoke herein disclosed comprises a pair of upper and lower cylindrical sections 10 and 11, of uniform cross section. At the top of the upper cylindrical section 10, the spoke is curved at right angles at 12, and terminates in a head 13 of usual construction, adapted to be engaged in a suitable socket on the hub of the wheel, not shown. The bottom portion 14 of the lower cylindrical section 11 is threaded, for a short distance near its end, to permit the spoke to be securely held in position on the vehicle wheel and adjusted to any desired tension by means of a suitable nipple not shown. secured to the wheel and adapted to be threaded on said spoke.

The central portion of the spoke between the upper and lower ends 10 and 11 is swaged down to form a relatively short cylindrical section 15. As more clearly, shown in Fig. 2, the section 15 is joined to the sections 10 and 11 by relatively long tapered sections 16 and 17 respectively.

It will thus be seen that a wire spoke has been provided which will have no swaged sections whatever at its ends, but instead has a short central cylindrical section whose length is relatively extremely short compared with the cylindrical section of the ordinary form of spoke in which the'central swaged port-ion comprises practically the entire length of the spoke. Moreover, with the present construction of spoke, the tapered portions 16 and 17 which join the swaged central section 15 to the cylindrical upper and lower sections 10 and 11 are relatively long as compared to-the tapered portions of the old formof spoke. 7

It has been found in practice that a spoke constructed according to; the invention has many advantages over the prior form of spokes. Fol-example, the breakage danger of'the spoke is very greatly diminished owing tothe reduction of the fatigue strains and crystallization throughout the wire.

Moreover, the construction of the spoke is such that the vibration will be transmitted from each end of the spoke to the central node there y, uniformly distributing the strains and making it practically impossible for breakage to occur near the ends of the spoke. e

Another advantage achieved by this invention is that in case the spoke is subjected to unusual stresses as in the case of an accident or the like, the rupture of the spoke will not occur near the rim of the wheel, but will always take place positively at the center.

While there has been disclosed in this specification one form in which the invention may be embodied, it is to be understood that this form is shown for the purpose of illustration only, and that the invention is not to be limited to the specific disclosure,

but may be modified and embodied in various other forms without departing from its spirit. In short, the invention includes all the modifications and embodiments coming within the scope of the following claims.

Having thus fully described the invention, what is claimed as new, and for which it is desired to secure Letters Patent, is:

1. A wire spoke for bicycle, automobile, or aeroplane wheels comprising a relatively short central section of small diameter, and relatively long end sections of larger diameter.

2. A wire spoke for vehicle wheels having a relatively short central cylindrical section of small diameter, and relatively long end sections of larger diameter.

3. A wire spoke for vehicle wheels hav ing a relatively short central cylindrical sec tion of small diameter, and relatively long end sections of larger diameter, said central cylindrical section having a length less than one-half of the total length of the spoke.

4. A wire spoke having a swaged central section of reduced diameter, a pair of tapered sections connected to said central section, a pair of end sections connected to said tapered sections, one of said end sections being threaded for a portion of'its length to be engaged by a nipple for tightening the spoke, the other end of said spoke being curved at right angles and having a head to be engaged in a socket in the rim of a wheel, said central swaged section having a length shorter than the length of either of said end sections.

5. A wire spoke for vehicle wheels having a relatively short central cylindrical section of small diameter, and longer end sections of larger diameter.

In testimony whereof, I have afiixed my signature to this specification.

JAMES H. GRAHAM. 

